As swash plate type liquid-pressure rotating devices, swash plate type axial piston pumps and swash plate type axial piston motors have been known. FIG. 11 shows one example of a conventional, typical swash plate type liquid-pressure rotating device 100. The swash plate type liquid-pressure rotating device 100 includes: a rotating shaft 3; a swash plate (not shown), a shoe plate 5a, a retainer plate 7, a spherical bushing 8, a cylinder block 9, and a valve plate 4 which are externally fitted to the rotating shaft 3 in this order from one side in an axial direction parallel to a center axis C of the rotating shaft 3; pistons 10 inserted into a plurality of bore holes 91 formed at the cylinder block 9; shoes 6 configured to spherically support respective tip ends of the pistons 10 and be in slide contact with the shoe plate 5a; and a set spring 20 provided between the spherical bushing 8 and the cylinder block 9. The retainer plate 7 is provided with a plurality of shoe support holes 71 corresponding to the bore holes 91. Spherical supporting portions 61 of the shoes 6 are inserted through the respective shoe support holes 71. Peripheries of the spherical supporting portions 61 are sandwiched between the swash plate and the retainer plate 7. The spherical bushing 8 rotates integrally with the rotating shaft 3 and spherically supports the retainer plate 7. The cylinder block 9 is pressed against the valve plate 4 by spring force of the set spring 20 and an action of liquid pressure in the bore holes 91, and the shoes 6 are pressed against a slide-contact surface 51 of the shoe plate 5a by the retainer plate 7 pressed by the spherical bushing 8.
In the swash plate type liquid-pressure rotating device 100 configured as above, when the cylinder block 9 rotates together with the rotating shaft 3, the pistons 10 perform reciprocating movements in the bore holes 91 along an inclination of the swash plate. When the swash plate type liquid-pressure rotating device 100 serves as the swash plate type axial piston pump, a predetermined amount of low-pressure operating fluid is suctioned to be ejected to a high-pressure side by the movements of the pistons 10. It should be noted that when the rotation of the rotating shaft 3 and the flow of the operating fluid in the swash plate type axial piston pump are reversed, the swash plate type liquid-pressure rotating device 100 serves as the swash plate type axial piston motor.
In the above swash plate type liquid-pressure rotating device 100, when a rotating speed of the rotating shaft 3 increases, reciprocating movement speeds of the pistons 10 increase, and this increases inertial force (shown by an arrow 101 in FIG. 11) by which the pistons 10 pull the shoes 6 toward the valve plate 4. Further, when the rotating speed of the rotating shaft 3 increases, centrifugal force (shown by an arrow 102 in FIG. 11) acting on the shoes 6 increases. Therefore, when force of pressing the shoes 6 against the swash plate exceeds the spring force of the set spring 20 by the increase in the rotating speed of the rotating shaft 3, a slide-contact surface 62 of the shoe 6 partially or entirely separates from the slide-contact surface 51 of the shoe plate 5a on the swash plate, and the shoe 6 falls down (hereinafter referred to as “tilts over”). The tilted-over shoe 6 partially contacts the slide-contact surface 51 of the shoe plate 5a on the swash plate. Therefore, uneven wear of the shoe plate 5a and the shoe 6 occurs, and galling, burning, or the like occurs therebetween. Thus, the shoe 6 and the shoe plate 5a are damaged.
To prevent the shoe from tilting over, the applicants of the present application devised a swash plate type liquid-pressure rotating device described in PTL 1. In the swash plate type liquid-pressure rotating device according to this conventional art, when assembling the swash plate type liquid-pressure rotating device, a gap (shown by an arrow G0 in FIG. 11) between the spherical bushing 8 and the cylinder block 9 in the axial direction is filled. With this, the retainer plate is prevented from moving in the axial direction.